This invention relates to multiposition expansible chamber actuators and more particularly to a three position vacuum actuator useful for control operations such as shifting valves, fresh air dampers and the like on automotive equipment or other apparatus.
Vacuum motors or differential pressure expansible chambers motors are well known to those skilled in the art and it has been previously proposed to utilize multiposition vacuum actuators particularly in the automotive field. For the most part, previously known multiposition vacuum actuators have not received widespread acceptance because of their complex construction both as to piping, internal valving, requisite external valving and as to an actual physical construction, e.g., overall length, needed to accommodate components such as housing extensions which were used to obtain three-position actuation.